SPOCK: It was, it was damaged in deep space. Undoubtedly, the meteor collision. Its memory banks were destroyed, or most of them. It wandered without purpose, and then it met the other. The other was an alien probe of great power. Somehow they merged, repaired each other, became one.

SPOCK: Not the Nomad we lost from Earth. It took from the other a new directive to replace its own. The other was originally programmed to secure and sterilise soil samples from other planets, probably as a prelude to colonisation.